Syringes have long been used as devices for measuring and dispensing liquids in laboratory and health care situations. Recent developments in laboratory processing have allowed the use of standardized 96 well microplates with 9 mm center-to center spacing, or 384 well microplates with 4.5 mm spacing. The Society of Biomolecular Screening (SBS) has established standard XY dimensions for multi-well microplates. This has allowed many processes to be automated. One such process uses sequencing gels for processing on an automated sequencer. Sequencing gels for automated sequencers are typically 0.2 mm or 0.4 mm thick. They are made of a porous matrix of cross-linked polymers sandwiched between two glass plates. The length and width of the gels can range in size up to approximately 30 cm.times.40 cm. Syringes are used to dispense samples so that they flow between the glass plates and onto the top of the gel which is about one centimeter below the top edges of the glass plates. The needles are therefore necessarily of a very narrow gauge. It has been found that grouping syringes into arrays is an efficient way to withdraw material from an entire row or column of a micro-well plate and transfer this material either to another micro-well plate or to a sequencing gel.
Sequencing gels can be configured for different numbers of "wells", each of which will hold a different sample. A well is essentially a chamber at the top surface of the gel where the surface of the gel is the well bottom and the sides of the well are formed by two "teeth" of a plastic "comb". A comb is inserted down between the plates until all the teeth contact the top of the gel and form the wells. The tops of the wells are open for samples to enter. Although width of a gel for a given automated sequencer generally stays the same, recently new sequencers have increased the number teeth in a comb, and thus increasing the number of wells present in a given gel. The result is that there are more, narrower wells with decreased center-to-center spacing of the wells. Syringe arrays that are to be used with these newer sequencers have had to deal with the change in center-to-center spacing either by having dedicated syringe arrays with fixed spacing which will accommodate only one such center-to-center spacing, or by attempting to adjust the spacing of the needle to match several different sequencers with different spacings. Prior art syringe arrays with adjustable spacing have provided sliding spreaders at the needle end of the syringes, which bend the needles so that the separation between them matches the center-to-center spacing of the wells. This has obvious disadvantages of causing stress and damage to the needles.
Thus there is a need for a syringe array with adjustable needle spacing which can match a variety of center-to-center spacings of sequencing gel wells without bending the needles of the array.